THF derivatives with a phenyl group at the C-4 position of the THF ring have been reported in the literature which bear a superficial resemblance to the THF derivatives of this invention. U.S. Pat. No. 4,404,127 describes the preparation of the THF derivatives shown below. Some of these compounds are new. The organoleptic properties of these compounds also are reported. All the THF derivatives claimed in this patent are described as fruity honey like, bloomy, or green. None of these THF derivatives are characterized as amber. ##STR3##
U.S. Pat. No. 4,549,029 describes the synthesis of novel THF derivatives with a six membered ring at the C-4 position of the THF ring. The substituent at C-4 on the THF ring has no more than seven carbon atoms. These structures are shown below. ##STR4## These compounds are described as citrus, fruity, floral, or grapefruit. None of these compounds is described as having an amber odor.
C. Sell, Chemistry & Industry, 516 (1990) discusses the chemistry of ambergris including a discussion of newly synthesized amber chemicals. In addition the Chapter entitled "The Fragrance Of Ambergris" by G. Ohloff in Fragrance Chemistry has a discussion of historical aspects related to ambergris, synthesis of amber chemicals, and structural studies. G. Ohloff, Fragrance Chemistry, Ernst Theimer Ed., Academic Press, New York, 1982. Additionally, a discussion of synthetic amber chemicals appears in G. Frater and D. Lamparsky, Perfumes, Art, Science, & Technology, P. M. Muller and D. Lamparsky Eds. Elsevier Applied Science, New York, 1991, p. 547. A discussion of structure-odor relationships in ambergris odorants appears in the same book by G. Ohloff, B. Winter, and C. Fehr at p. 287.
Ambergris is a secretion of the blue sperm whale. It is found in the intestinal tract of the animal. One of the major components of ambergris is the triterpene ambrein. Ambrein itself is odorless, but as ambrein is broken down outside the whale, the characteristic ambergris odor develops. Some of the compounds responsible for the odor of ambergris are shown below. ##STR5##
The important components in this mixture are the perhydronaphthofuran and the octahydronaphthalenol. These materials are commercially produced and they are shown below. The perhydronaphthofuntn is known by various tradenames. These include Ambrox.RTM., Ambroxan.RTM., and Amberlyn.RTM.. ##STR6## The octahydronaphthalenol is known as Ambrinol.RTM.. Ambrox is a highly prized perfume component known for its very free amber odor and fixative properties. It is an expensive perfume chemical. Ambrinol is known for its animal and earthy quality. It is less used but also very expensive. Ambrox was first synthesized by Stoll and Hinder in 1950. M. Stoll and M. Hinder, Helv. Chim. Acta, 33, 1251 (1950); M. Stoll and M. Hinder, Helv. Chim. Acta, 36, 1995 (1953). More recent syntheses of Ambrox are compiled in G. Frater and D. Lamparsky, Perfumes, Art, Science, & Technology, P. M. Muller and D. Lamparsky Eds. Elsevier Applied Science, New York, 1991, p. 547. Paquette and Maleczka have recently reported on a highly convergent synthesis of 9-epi-Ambrox and a minor perhydronaphthopyran component found in ambergris. R. E. Maleczka and L. A. Paquette, J. Org. Chem., 56, 6538 (1991).
Commercial syntheses of Ambrox start with the plant clary sage (Salvia sclarea) in which the diterpene sclareol is present. Sclareol is shown below. A degradative pathway involving ##STR7## oxidative cleavage, reduction and cyclization has been developed by various workers. L. Ruzicka, C. F. Seidel, and L. L. Engel, Helv. Chim. Acta, 25, 621 (1942); H. R. Schenk, H. Gutmann, O. Jeger, and L. Ruzicka, Helv. Chim. Acta 35, 817 (1952); R. Decorzant, C. Vial, F. Naf, and G. M. Whitesides, Tetrahedron, 43, 1871 (1987); and U.S. Pat. No. 4,798,799.
Ambrinol also has been synthesized by a number of routes. M. Stoll and M. Hinder, Helv. Chim. Acta 38, 1593 (1955); M. Stoll C. F. Seidel, B. Willhalm, and M. Hinder, Helv. Chim. Acta 39, 183 (1956); A. G. Armour, G. Buchi, A. Eschenmoser, and A. Storni, Helv. Chim. Acta 42, 2233 (1959) footnote 8; P. Christenson, B. Willis, F. Wehrli, and S. Wehrli, J. Org. Chem., 47, 4786 (1982); and P. Naegeli and Y. Wirz-Habersack, Tetrahedron Asymmetry, 3,221 (1992). It is the only commercial product available from synthetic starting materials, namely (.+-.)-dihydro-.GAMMA.-ionone. ##STR8##
All these previous routes to amber chemicals are expensive. There is a need for cheaper amber chemicals which are more industrially accessible. Vlad reports the preparation of an amber THF derivative shown below. P. F. Vlad, A. F. Morary, and M. N. Koltsa, SU 1169971 (1983) This compound is a C-2,3 disubstituted ##STR9## tetrahydrofuran with a substituent at C-3 of the THF ring with eleven carbon atoms. This is substantially different from the compounds claimed in this disclosure.
Sell and coworkers report the preparation and odor properties of some 1,3-dioxane derivatives. EP 276 998 A2. Some of these compounds are shown below. They are completely unrelated to the compounds claimed herein. ##STR10##
Another series of amber smelling 1,3-dioxanes are reported in EP 266 648 A2. The general structure is shown below. These compounds are not related to the compounds claimed herein. ##STR11##
Some spirocyclic THF derivatives have been reported to possess an amber odor. Chodroff and Vazirani report the bicyclic compounds shown below are amber in odor characteristic. U.S. Pat. No. 3,417,107. These spirocycles are 3-substituted THF derivatives with no other substituents on the THF ring. They are completely unrelated to the THF derivatives of this invention. ##STR12##